Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/02—Preparing or treating the raw materials individually or as batches
  • C04B33/13—Compounding ingredients
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/02—Preparing or treating the raw materials individually or as batches
  • C04B33/13—Compounding ingredients
  • C04B33/132—Waste materials; Refuse; Residues
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/02—Preparing or treating the raw materials individually or as batches
  • C04B33/13—Compounding ingredients
  • C04B33/132—Waste materials; Refuse; Residues
  • C04B33/1324—Recycled material, e.g. tile dust, stone waste, spent refractory material
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/02—Preparing or treating the raw materials individually or as batches
  • C04B33/13—Compounding ingredients
  • C04B33/14—Colouring matters
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/02—Preparing or treating the raw materials individually or as batches
  • C04B33/13—Compounding ingredients
  • C04B33/18—Compounding ingredients for liquefying the batches
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/30—Drying methods
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B33/00—Clay-wares
  • C04B33/32—Burning methods
  • C04B33/34—Burning methods combined with glazing
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/62605—Treating the starting powders individually or as mixtures
  • C04B35/62625—Wet mixtures
  • C04B35/6263—Wet mixtures characterised by their solids loadings, i.e. the percentage of solids
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
  • C04B2235/3206—Magnesium oxides or oxide-forming salts thereof
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
  • C04B2235/3208—Calcium oxide or oxide-forming salts thereof, e.g. lime
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/327—Iron group oxides, their mixed metal oxides, or oxide-forming salts thereof
  • C04B2235/3272—Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3418—Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
  • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Definitions

• the present invention relates to a ceramic composition which is particularly well suited for quick firing, consisting mainly of a lime component, a clay component, and water, and a method for manufacturing the ceramic compound and its utilization for manufacturing stoneware products.
• stoneware compositions for lime or feldspar stoneware are produced in large quantities for the manufacturing of ceramic products, especially wall tiles and crockery.
• Clays, quartz powder, calcareous spars and fluxing materials such as feldspars, syenites etc. are generally used as main raw materials.
• These stoneware compounds are fired at temperatures of approximately 1000°-1100° C. They must be heated slowly and fired over a long period of time. A common firing period is about 24 hours.
• compositions which are suitable for quick firing are manufactured on the basis of clay-wollastonite or clay-talc-dolomite. In Germany, and also in Middle Europe, such compositions are not utilized, as no suitable raw materials are available, i.e. there are no local deposits of wollastonite and talc. Attempts have been made to synthesize wollastonite or other calcium silicates (e.g. diopside) and use these as raw materials in the ceramic industry. The types of compositions manufactured by synthetic wollastonite have very good qualities with regard to quick firing. Within the wall tile industry, however, wollastonite has not been used as a raw material in quantities worth mentioning, as wollastonite is too expensive for such use.
• a ceramic composition a major proportion of which is constituted by a lime component, a clay component, and water, in which the lime component is a hydrothermally cured, highly porous lime-sand product having a major proportion of spherical pores.
• the composition is prepared by grinding together a conventional stoneware clay and the lime-sand product, forming an aqueous castable slurry of the ground material, drying the slurry and granulating the dried material.
• Stoneware is made by pressing the composition into a desired shape, drying, and then firing at temperatures of 900° to 1100° C. The composition can be quickly fired in not more than six hours, without the adverse effects resulting from attempts to quickly fire conventional inexpensive stoneware compositions.
• the lime component is a product, made mainly of a mixture of lime, cement, quartz sand, water and expanding or foaming agents.
• cement and quartz sand are thoroughly mixed batchwise in a mixer, adding water and expanding or foaming agent.
• Degreased aluminium powder, hydrogen peroxide, chloride of lime, or the like can be used as a gas developing expanding agent.
• the mixture is cast in a mould and gas is immediately evolved by the gas producing agent which forms the porous structure.
• chemical binding of the lime and silicate material begins.
• the mass sets to "green" strength in about 1 hour.
• the material is subjected to hydrothermal curing.
• a typical cure is 8-10 hours at 180° C. at a pressure of about 10 Kg/cm 2 .
• quartz sand of a grain size of 90% by weight less 90 ⁇ m 55-85% by weight of quartz sand of a grain size of 90% by weight less 90 ⁇ m.
• the most favorable mixture contains (dry weight basis):
• quartz sand of a grain size of 90% by weight less 90 ⁇ m 75% by weight of quartz sand of a grain size of 90% by weight less 90 ⁇ m.
• the cured lime component has a volume weight of approximately 0.4-0.8 g/cm 3 and a porosity of approximately 60-90%, the main part of the pores being spherical. It is mainly built up of quartz grains, puttied together in a binding agent structure of calcium silicate hydrates, wherein the portion of quartz grains may amount to about 60-80% by weight.
• Such products are per se known as form products and are known as cellular concrete or other terms such as gas concrete, lightweight concrete and foam concrete.
• Their chemical composition is approximately the following:
• the ceramic composition in accordance with the invention contains ordinary commercial stoneware clays and the lime component described above in a ratio of components by weight clay substance:lime component of 95:5 to 40:60, preferably between 75:25 and 50:50.
• the composition contains about 4-8%, preferably about 6%, by weight of water and, optionally, conventional fluxing agents for ceramics, such as feldspar, preferably in amounts of 2-10% by weight.
• ordinary commercial stoneware clays are ground, adding about 30% by weight of water with the lime component, preferably in a ceramic ball mill, to avoid ferruginous contamination, until a ceramic slurry, suitable for casting, has formed.
• conventional fluxing materials such as feldspars, can also be ground in, in quantities of about 2-10% by weight. Grinding agents, preferably in quantities between 0.1 and 0.7% by weight, may also be added. As grinding agents, preferably conventional materials containing water glass or soda are used.
• the slurry is then dried to a moisture content of about 6% by weight, preferably by spray drying, and the resulting compound is granulated.
• the granulated ceramic compound in accordance with the invention is pressed into blanks of desired shape.
• the blanks are dried in the usual way and acquire a very good green strength.
• the material is particularly well suited for glazing, due to its favorable pore structure. They are preferably fired by a quick firing process at temperatures of 900°-1100° C., preferably 1000°-1050° C., whereby the firing cycle is carried out in 1-6 hours, preferably 2-4 hours.
• the blanks which have been pressed out of the ceramic composition in accordance with the invention are, of course, suitable for longer firing schedules such as the conventional 24 hour schedule mentioned above.
• 100 Kg of stoneware clay is dispersed with 60 Kg water in a ceramic ball mill.
• 1 Kg of alkali polyphosphate grinding agent (Formsil AP, trade name, produced by Henkel International) is also mixed into the aqueous dispersion.
• the dispersion is ground, non-ferruginously, with 100 Kg cellular concrete waste in a ceramic ball mill for 2 hours.
• the slurry thus obtained is dried with hot air to a moisture content of 6% by weight of water, granulated, and pressed into a blank in a wall tile press.
• the blank is dried in a drying tunnel at 110° C. and fired in a through-oven for 2 hours at 1000° C.
• the fired product is cream-colored and has a bending strength of 180 Kg/cm 2 .
• a glazing is applied, which is fired in at 950° C.
• the adherence of the glazing as well as the lustre and evenness are perfect.
• An autoclave test shows that the product is stable as to form against the influence of moisture.
• the fired product has a very good bending strength, in all cases corresponding to the values required in accordance with DIN 18155.
• the shrinkage is quite low, less than 1%.
• the product has a very light color, cream-colored to light-brown.
• a substantial advantage of products made of the ceramic composition of the invention is that they hardly have any moisture dilatation at all, and therefore do not cause any capillary cracks in the glazing.
• the raw material costs for the ceramic composition of the invention are quite low in comparison with known calcium silicates, due to the utilization of the particular lime component. It should especially be pointed out that, e.g., waste material which is had in large quantities when manufacturing cellular concrete, or cellular concrete products which cannot be disposed of within the building sector, may be used as a cheap lime component. Since in the cellular concrete manufacture, great importance is normally attached to the uniformity in the composition of the raw material mixture, the composition of the cured products useful in the present invention is subject only to small variations. Due to this uniformity those products are especially suitable to be used for preparing a ceramic composition, even where the products are regarded as waste material in the building sector.
• the very porous lime component is not at all suggested in the prior art.
• this component is, e.g., also porous in its most fine-grained constituents so that it could be expected that the structure should partly only deform elastically at pressing, and the blank be loosened after pressing, by the elastic after-effects on the structure.
• This phenomenon is, for instance, well known with the use of mica.
• small particles of clay penetrate the pores of the lime component and support the structure at the pressing in such a way that no perceivable elastic deformation occurs.
• the utilization of the hydrothermally cured lime component in a ceramic compound is advantageous for ceramic firing, especially since the calcium silicate hydrate phases as well as the quartz grains, which are superficially dissolved during the hydrothermal process, and further the clay substances all have a high activating energy at temperatures of 500°-600° C. so that reactions in solid phase are facilitated and thus any possible sintering agents are not required. The consequence of this will be reactions of high velocity in solid phase and therefore very short firing periods are possible.
• fired products with particularly high strength and -- contrary to known stoneware products -- with a surprisingly good glazing affinity are obtained from the ceramic composition of the invention. Therefore, very good firing results with regard to lustre and evenness can be obtained with practically any conventional glazing.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Dispersion Chemistry (AREA)
• Environmental & Geological Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Inorganic Chemistry (AREA)
• Compositions Of Oxide Ceramics (AREA)
• Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Porous Artificial Stone Or Porous Ceramic Products (AREA)

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Citations (4)

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• 1975
  • 1975-07-29 DE DE2533774A patent/DE2533774C2/de not_active Expired
• 1976
  • 1976-01-15 AT AT0025176A patent/AT373228B/de not_active IP Right Cessation
  • 1976-06-08 SE SE7606407A patent/SE426235B/sv unknown
  • 1976-07-08 US US05/703,605 patent/US4119470A/en not_active Expired - Lifetime
  • 1976-07-26 JP JP51088316A patent/JPS5230809A/ja active Granted
  • 1976-07-27 CH CH961076A patent/CH623801A5/de not_active IP Right Cessation
  • 1976-07-27 NL NL7608330A patent/NL7608330A/xx not_active Application Discontinuation
  • 1976-07-29 BE BE169383A patent/BE844684A/xx unknown

Patent Citations (4)

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